1. Technical Field
This application relates to computer storage devices, and more particularly to the field of efficiently using computer storage devices to perform data operations.
2. Description of Related Art
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units (host adapters), disk drives, and disk interface units (disk adapters). Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. Nos. 5,206,939 to Yanai et al., 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels of the storage device and the storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical volumes. The logical volumes may or may not correspond to the actual disk drives.
Some applications, such as database applications, cause the host to perform a significant number of accesses to the storage device. In addition, applications like database applications cause a significant amount of data to be exchanged between the host and a storage device, thus using data bandwidth that could be used for other purposes, including improving the throughput of other applications. Accordingly, it is desirable to provide a mechanism that allows database operations to be performed on the storage device to eliminate or reduce the significant amount of accesses and data transfers between the storage device and the host. It would also be desirable in some circumstances to be able to shift CPU cycles associated with database operations from the processor(s) of the host to the processor(s) of the storage device.